Casting metal



March 23, 1943. D. J. CAMPBELL CASTING METAL 4 Sheets-Sheet 1 Do /a aallbul Filed May 19, 1941 lnn cntor Y /hmtulf. Dakz dttorncg March 23,1943.

D. J. CAMPBELL CASTING METAL Filed May 19. I l-941 4 Shee ts-Sheet 2Dona lC myfib -l/ 3|wentor (Ittqrneg March 23, 1943- D. .L CAMPBELLCASTING METAL 4 sheat s-Sheet s Filed May 19, 1941 Inventor dttorncglMarch 23, 1943- o. J. CAMPBELL CASTING METAL 4 Sheets-Sheet 4 Filed May19, 1941 3 nnentor DO /a lea 11,111

" M Dd/aa (Ittorneg UNITED STATES PATENT OFFICE i v CASTING METAL DonaldJ. Campbell, Spring Lake, Mich. Application May 19, 1941, Serial No.394,068 3 Claims. (Cl. 22-200) My present invention relates toimprovements in casting metal, and particularly to the method andapparatus employed in practicing'improved I attain these named objects.and such other objects as appear from a perusal of the followingdescription, by the apparatus disclosed in the several views of theaccompanying drawings, in which- Figure 1 is a diagrammatic view ofportions of the apparatus employed in practicing my present method ofcasting metal.

Figure 2 is a top plan view ofthe mold employed in my present method.

Figure 3 is a cross-sectional view of the mold employed and taken on aplane extending downward from line 1-1, of Figure 2, and looking in thedirection the arrows crossing the line indicate.

Figure 4 is a transverse sectional view of the said mold taken on lineII II, of Figure 3, and looking in the direction the arrows thereonindicate.

Figure 5 is a transverse sectional view of the said mold taken on lineV--V, of Figure 3, and looking in the direction the arrows thereonindicate.

Figure. 6 is a transverse sectional view of the said mold taken on lineX-X, of Figure 3, and looking in the direction the arrows thereonindicate; and,

Figure 7 is a longitudinal part sectional view of a gun projectile aswould be cast by my present method hereinafter described andby the useof the apparatus illustrated in the accompanying drawings,inwhichSimilar numerals refer to similar parts or portions throughout theseveral thereto.

Numeral l refers to the intermediate, or cheek portion of a mold formedwithin the foundry flask views, and referring portion 5 of the mold issurrounded by flask 10K and has at its axial center, pour sprue hole llwith flaring portion i2 at its top and thereabove,

. pour basin I3 with skim gate l4 therein, and in its lower face, runnergates l5 extending from the i the mold portions I and 6. The draft pipe8 2, and having mold cavities 3 of such form as would be adapted forcasting therein, large caliber gun projectiles, such as shown in Figure'7 of the accompanying drawings; The said cavities 3 are partly closed'at their top: by core like slabs I having v tt nding therethrough, andinto the cope portion 5" of the mold, feeder cavitiesi and from the topthereof extended cavities 1 open to the interior of draft pipe 8 throughholes 9. The cope which is surrounded at the sand of the cope portionof'the mold has communication with the cavities I through holes 9 andextends through the side of the flask lo and exterior of the mold whereit is detachably connected with hose 2| and thereby to the air pump 22driven by motor 23 of any suitable design. At the lower extremity of themold portion I is core like slab 24 surrounding the lower end of themold'cavities' 3'and portion' 25 of the extended portion of the spruehole 26. The said core like slab, has encircling the lower ends of themold cavities 3, runner passages 21 from which extends moldfeederpassages 28 to the portion 25 of the sprue hole 26. Below the core likeslab 24 is a-second core lik slab 29 having annular runner passages 30with radial gates 2| extending therefrom inward and upward to the moldcavities 3. The said core like slab.

'29 has at its central axis, basin :2 and directly below the moldcavities 3, holes through which extends hollowiperforated core arbor 34having longitudinal neck 34' and built thereon, first, a

rope like fibrous material on which is built the core 35 of suitablegranular material, the said cores each have neck portions 36 whereby isformed the hole in the apex of each projectile.

The said core arbors each have a co'nicalfportion 31 socketedintoconical holes 38 of the hollow bottom plate 39 of the mold arborwith their longitudinal holes 40 open to the cavity 4| having a hole 42closed by plate, which hole is provided for cleaning the interior of thebottom plate which has extending from the cavity 4i thereof, pipe 44"connected in like manner to a similar air pump to the pump 22 shown inFigure-1 91 the drawings.

In practicing my method of casting metal, which in the instant case isthe casting,of.large caliber gun projectiles; having provided theapparatus including a mold substantially as described with the air pumpsconnected to the mold as shown; I start the said air. pumps as bystarting the motors having shaft connection therewith by the usualswitch that closes an electric-circuit, and in starting the air pumpsgas is drawn forations and longitudmalhole 31' or the aroor,

and by the plnnp connected'to the draft pipe 8, drawgas directly fromthe molten metal through the holes 9 and I at the top at each of thefeeder cavities at.the.top of the mold; and by drawing the gas from thecores, I. permit the molten metal to lay up againstthe cores withoutcausing gas pockets or blows, and in drawing gas directly from themolten metal, which is steel in projectiles, all voids within the metalare eliminated and the steel of uniform structure free from dirt,

slag.

While the pumps drawing the gas from the core and metal, are referred toas air pumps, it

' is to be understood such pumps are classed as air pumps which areequally useful for pumping gas as well as air. In the usual method ofcasting metal, particularly steel, greatloss of good castings are causedI by reason of the gas formed in the metal by melting forming gascavities or pockets in the casting and in the core formingthe moldcavities also causing gas cavities and blow holes or depressions in thecastings.

In castings, the molten metal which in casting projectiles such asshown, is steel, is poured from a foundry ladle into the pour basin [3from where it flows downward through the skim gate ll into the flaringportion of the sprue hole II and downward through the sprue hole to thebasin 32 and radially outward to through passages 28 to the annular ringpassage 21 from where it flows feeder cavities to remain in a fluidstate after the lowerportion of the molten metal in the mold cavitieshas solidified and thus: providing molten metal to feed from the feederc'avities to the mold cavities to compensate for shrinkage of thecastings in the mold cavities. It should be understood that. the spruehole II is less in cross-sectional area than the sprue hole 26 and thatthe enlarged portion extending through the core like slab 4 is stilllarger, thereby preventing molten metal entering the top of the moldcavities until the molten metal rises to above the said core like slab.

vThesprue hole by which the molten metal is conducted to the runnergates at the lower portion of the mold, consists of the outwardlyflaring funnel like portion that receives the molten metal from the skimgate II, a restricted portion l l of less cross-sectional area than'theskim gate, and therefore less capacity, an enlarged pass portion betweenthe restricted portion II and an elongated portion 26 having a greatercross-sectionaliarea than the said restricted portion H but less thanthe said enlarged pass portion and the combined area of the runner gatesextending to the mold cavities at their lower ends and therefore thesmall ends of the mold cavities where gun projectiles are being cast.The molten metal delivered to the mold cavities through the runner gatesat the lower end of the moldcavities,

therein and in doing so, cools and therefore 5111111 llLlbLl 1b rcauuusbut: .ucuvy put uuu ul. ulcprojectile, which because of its greater massthan the side walls of the projectile, remain in a molten state andfeeds molten metal to the side wall portions during their period ofsolidification and shrinkage, and the heavy portion remaining fluidafter the said side walls have solidified, draws molten metal from thefeeder cavities 6 until the metal in the heavy portion of theprojectiles has solidified.

In conducting casting by my method and having provided the moldsubstantially as described, and the molten metal which in castingprojectiles consists of steel; I start the air pump, connected to thepipe 8 having connection with the mold cavities in the cope portion ofthe mold, the hollow supporting plate at the bottom of the mold, orboth, and thereby cause a partial vacuum within the mold cavities, andpour the flows through the sprue and gate passages to v the moldcavities, helped by the partial vacuum within the said mold cavities andby the partial vacuum draws from' the metal gases formed therein andsuch as are formed in the cores therefrom and therefore produces metalcastings free from gas cavities or pockets and internal defects.

Having described my method of casting metal and the apparatus whereby Ipractice said method; I claim:

1. In casting metal, the method consisting of applying suctionsimultaneously to a ,core within a mold cavity and a feeder cavity of amold having a plurality of mold cavities therein, a runner sprue forflowing molten metal to the mold cavities and having a plurality ofportions of different cross-sectional areas comprising a choke portionan enlarged portion below the said choke portion and a third portionhaving a greater cross-sectional area than the choke portion andextending below the said mold cavities with a plurality of runner gatesextending to the lower end of said mold cavities and runner gatesextending from the said enlarged portion to the upper portion of saidmold cavities while the metal in the mold is in a molten state, causinga partial vacuum within the said mold cavities by applying suction tothe mold cavities at their top and to the cores in the mold cavitiesthrough the core arbors simultaneously.-

2. In casting metal, the method consisting in providing a moldhaving acasting cavity with a feeder cavity above the casting cavity and ahollow core supported in the casting cavity and drawing gas from the topof the feeder cavity while drawing gas from the casting cavity downwardthrough the core substantially as described.

3. In casting metal, the method consisting in providing a mold having acasting cavity with a feeder cavity above the casting cavity and a core.having a hollow core arbor extending upwardly within the mold cavitywith a core built onto and around the core arbor, drawing air from-thecasting cavity, depositing molten metal in the said casting cavity andagainst the said core, drawing air and gas from the casting cavityupwardly through the feeder cavity and drawing gas from the said coredownward through the core arbor substantially as described.

DONALD J. CAMPBELL.

